1. Field of Invention
The present invention generally relates to an antenna array, and more particularly to an antenna array with a simple production process and lower side lobe energy dissipation of its radiation pattern.
2. Description of Prior Art
Currently, the conventional antenna array includes a grounding plate, radiation conductors, a signal transmission part, and a signal feed cable. Wherein, the radiation parts are set on the top side of the grounding plate, and the signal transmission part is connected between the radiation conductors. The signal feed cable includes a central conductor connected to the signal transmission part and an outer conductor connected to the grounding plate. The signal feed cable is used to feed the high frequency signal into the conventional antenna array.
The high frequency signal may leak its energy when transmitting in the signal transmission part, and thus an energy loss occurs. Further, because the signal transmission part and the radiation conductors of the conventional antenna array are sited at the same side of the grounding plate, the radiation pattern of the conventional antenna array may be interfered by the leaking energy. Thus, the energy of the side lobe in the radiation pattern of the conventional array may increase, and according to the law of the energy conservation, the increasing of the energy of the side lobe decreases the signal level of the main lobe of the conventional antenna array. Furthermore, when the distance between the signal transmission part and the grounding plate is large, the input impendence of the conventional antenna array may be large too, and thus the impendence match of the conventional antenna is hard to be achieved. Accordingly, the signal transmission part of the conventional antenna array may be bent to approach the grounding plate. Thus, the transmission impendence of the signal transmission part may be lowered, and the impendence match may be achieved.
Contrary to the design of making the signal transmission part approach to the grounding plate, the efficiency of the radiated signal of the conventional antenna array may increase when the distance between the radiation conductors and the grounding plate increases. That is, the gain of the whole radiated signal may be enhanced when the distance between the radiation conductors and the grounding plate is large.
The radiation conductors and the signal transmission part are connected to each other, but the design of the distance between the radiation conductors and the grounding plate and the design of the distance between the signal transmission part and the grounding plate are opposite to each other. Therefore, the radiation conductors and the signal transmission part must be sited on the different heights, and the difficulty of producing the conventional antenna array may increase. Thus the impendence of the conventional antenna array may be hard to adjust and match, the stability of conventional antenna array may decrease, and the production cost of the conventional antenna array may increase. In addition, for the conventional antenna array, the isolation level of the radiation conductors may decrease when the distance between the radiation conductors is too short. That is, the interference thereof may occur, and the radiation pattern of the conventional antenna array is affected.
In order to solve these and other problems as stated above, the exemplary embodiment of the present invention provides an antenna array with a simple production process and lower side lobe energy dissipation of its radiation pattern.